Electrochemical Apparatus and Electric Device Including Same

This application is a continuation application of International Application No. PCT/CN2023/099742, filed on Jun. 12, 2023, the contents of which are incorporated herein by reference in its entirety.

This application relates to the field of energy storage apparatuses, and in particular, to an electrochemical apparatus and an electric device including the same.

Electrochemical apparatuses (for example, lithium-ion batteries) are widely applied to electric vehicles and consumer electronic products due to their advantages such as high energy density, high output power, long cycle life, and little environmental pollution. However, electrochemical apparatuses may encounter safety issues such as fire upon abnormal conditions such as squeezing, collision or puncture.

An objective of this application is to propose a battery with good cycling performance and capable of reducing the risk of internal short circuits in electrochemical apparatuses.

This application provides an electrochemical apparatus, including a housing, an electrode assembly, a first insulating layer, and an electrolyte. The electrode assembly and the electrolyte are accommodated in the housing. The electrode assembly includes a plurality of electrode plates stacked along a first direction and first separators disposed between the plurality of electrode plates. The electrode assembly further includes a first surface and a second surface opposite each other in the first direction, as well as a first end face connected between the first surface and the second surface. The first insulating layer is adhered to all the first surface, the second surface, and the first end face. The first separator includes a substrate layer, and first coatings spaced apart on a surface of the substrate layer facing an adjacent electrode plate.

In this application, the first insulating layer is connected to the first surface, the second surface, and the first end face of the electrode assembly, where the first insulating layer constrains the electrode assembly in the first direction, reducing the risk of internal short circuits caused by shrinkage of the first separator, thereby improving the safety performance. However, constraining the electrode assembly in the first direction with the first insulating layer may reduce a gap between the first separator and an adjacent electrode plate, reducing space available for electrolyte transport and leading to poor electrolyte infiltration. This application provides a first separator including a plurality of first coatings spaced apart, where a gap between two adjacent first coatings reserves space for electrolyte transport, improving an electrolyte infiltration effect, and mitigating lithium precipitation issues on the electrode plate caused by poor electrolyte infiltration, thereby improving the cycling performance. Therefore, the electrochemical apparatus of this application achieves high cycling performance while maintaining the safety.

In some possible implementations, the first coating is strip-shaped, the substrate layer includes two side edges opposite each other in a second direction perpendicular to the first direction, and the plurality of first coatings are obliquely arranged with respect to the side edges. Thus, the adhesive strength between the first coating and the adjacent electrode plate is continuously distributed across each edge of the electrode assembly, enhancing the deformation resistance of the electrode assembly and improving the cycling performance.

1 1 1 In some possible implementations, when viewed in the first direction, an included angle between the first coating and the side edge is θ, where 25°% θ≤65°. When the included angle θis within this range, the adhesive strength between the first coating and the edge of the electrode plate can be maintained, suppressing edge deformation of the electrode plate, thereby improving the cycling performance.

1 2 2 1 2 1 2 2 1 2 In some possible implementations, when viewed in the first direction, a width of the first coating is D, and a spacing between two adjacent first coatings is D, where 0.3D≤D≤0.5D. When D>0.5D, upon a fixed electrode plate area, a smaller Dreduces the space available for electrolyte transport, which causes poor electrolyte infiltration, exacerbating lithium precipitation issues on the electrode plate, and affecting the cycling performance. When D<0.3D, an adhesion area between the first coating and the electrode plate is reduced, the adhesive strength is reduced, and the deformation resistance is reduced accordingly, affecting the cycling performance.

In some possible implementations, the first separator further includes a plurality of second coatings, the plurality of second coatings are spaced apart on a surface of the substrate layer facing away from the plurality of first coatings. A gap between two adjacent second coatings reserves space for electrolyte transport, improving the electrolyte infiltration effect, and further mitigating lithium precipitation issues on the electrode plate caused by poor electrolyte infiltration, thereby improving the cycling performance.

In some possible implementations, the first coatings and the second coatings are spatially interdigitated, such that gaps between adjacent first coatings and gaps between adjacent second coatings are staggered, further improving the electrolyte infiltration effect and further mitigating lithium precipitation issues on the electrode plate caused by poor electrolyte infiltration, thereby improving the cycling performance.

In some possible implementations, the first separator further includes a plurality of first portions located among a plurality of electrode plates, as well as a second portion and a third portion located outside the plurality of electrode plates and opposite each other in the first direction, and each first portion is disposed between two adjacent electrode plates. The plurality of first portions, the second portion, and the third portion are integrally disposed to form a wound structure. The first separator is configured as a wound structure, constraining the plurality of electrode plates in a plurality of different directions, without providing an additional insulating layer to constrain the plurality of electrode plates in specific directions. Furthermore, the first insulating layer is connected to the second portion and the third portion of the first separator, increasing the adhesive strength between the first insulating layer and the electrode assembly, and reducing the risk of detachment of the first insulating layer, thereby reducing the risk of internal short circuits caused by shrinkage of the first separator.

1 2 1 2 1 1 2 In some possible implementations, in a third direction perpendicular to both the first direction and the second direction, a width of the electrode assembly is W, and a width of the first insulating layer is W, where 0.7W≤W≤W. When the width Wof the electrode assembly and the width Wof the first insulating layer are within this range, the adhesive strength between the first insulating layer and the first end face can be maintained, reducing the risk of internal short circuits caused by shrinkage of the first separator, thereby improving the safety performance.

1 2 1 1 2 1 In some possible implementations, 0.7W≤W≤0.95W. In some possible implementations, 0.85W≤W≤0.95W.

In some possible implementations, the first coating includes a first inorganic particle layer and a first adhesive layer, the first inorganic particle layer is connected to the substrate layer, and the adhesive layer is disposed on a surface of the inorganic particle layer facing away from the substrate layer and is adhered to an adjacent electrode plate. The first adhesive layer is adhered to the electrode plate, enhancing the interfacial adhesive strength between the first separator and the electrode plate, reducing swelling deformation caused by gas generation inside the electrochemical apparatus, and improving the cycling performance.

In some possible implementations, the first coating includes inorganic particles and a binder.

In some possible implementations, the electrochemical apparatus further includes a second insulating layer, the electrode assembly further includes a second end face connected between the first surface and the second surface, a length direction of the electrode assembly is defined as the second direction, the first surface and the second surface are opposite each other in the second direction, and the second insulating layer is connected to all the first surface, the second surface, and the second end face. Connecting the second insulating layer to the first surface, the second surface, and the second end face of the electrode assembly reduces the risk of internal short circuits caused by shrinkage of one end of the first separator close to the second end face.

In some possible implementations, the first insulating layer is a single-sided adhesive or a double-sided adhesive.

In some possible implementations, the second insulating layer is a single-sided adhesive or a double-sided adhesive.

In some possible implementations, the electrochemical apparatus further includes a first metal plate and a second metal plate, and the first metal plate and the second metal plate are both connected to the electrode assembly. In a third direction perpendicular to the first direction, the electrode assembly further includes a second end face opposite the first end face, and the first metal plate and the second metal plate extend out of the electrode assembly from the second end face.

In some possible implementations, the housing is a packaging bag.

This application further provides an electric device, including any one of the electrochemical apparatuses described above.

The technical solutions in the embodiments of this application are described clearly in detail below. It is apparent that the described embodiments are some rather than all of the embodiments of this application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of this application. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

The embodiments of this application are described in detail below. However, this application may be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided to thoroughly and completely convey this application to those skilled in the art.

In addition, for brevity and clarity, the dimensions or thicknesses of various components and layers in the drawings may be exaggerated. Throughout the specification, the same reference numerals refer to the same elements. It should also be understood that when an element A is referred to as being “connected” to an element B, element A may be directly connected to element B, or there may be an intermediate element C, and element A and element B may be indirectly connected to each other.

Further, in the description of the embodiments of this application, the term “may” refers to “one or more embodiments of this application”.

The technical terms used herein are for the purpose of describing specific embodiments and are not intended to limit this application. As used herein, singular forms are intended to include plural forms as well, unless clearly indicated otherwise in the context. It should be understood that the term “include”, when used in this specification, refers to the presence of the stated features, values, steps, operations, elements, and/or components, but does not preclude the presence or addition of one or more other features, values, steps, operations, elements, components, and/or combinations thereof. It should be understood that, although the terms such as first, second, and third may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below may be referred to as a second element, component, region, layer, or section without departing from the instruction of the exemplary embodiments.

In this application, “a plurality of” refers to two or more.

In this application, the electrochemical apparatus includes any apparatus in which an electrochemical reaction takes place, and specific examples thereof include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. For example, the electrochemical apparatus is a lithium secondary battery, and the lithium secondary battery may include a lithium metal secondary battery, a lithium-ion secondary battery, a lithium polymer secondary battery, or a lithium-ion polymer secondary battery.

1 FIG. 2 FIG. 3 FIG. 2 FIG. 3 FIG. 100 10 20 10 30 40 10 10 100 100 20 100 20 Referring to, an embodiment of this application provides an electrochemical apparatus, including a housing, an electrode assembly(shown inand) and an electrolyte that are accommodated in the housing, a first metal plate, and a second metal plate. In some embodiments, the housingis a metal housing, such as a steel housing or an aluminum housing. In some other embodiments, the housingis a packaging bag formed by sealing an encapsulation film, that is, the electrochemical apparatusmay be a pouch battery.andshow that the electrochemical apparatusincludes one electrode assembly. In some other embodiments, to achieve high voltage output, the electrochemical apparatusincludes a plurality of electrode assemblies.

4 FIG. 20 23 20 21 22 23 21 22 21 22 As shown in, the electrode assemblyincludes a plurality of electrode plates and first separatorsdisposed among the plurality of electrode plates. The plurality of electrode plates are stacked along a first direction Z to form a stacked structure. In this embodiment, the first direction Z refers to a thickness direction of the electrode assembly. The plurality of electrode plates include a first electrode plateand a second electrode platewith opposite polarities. The first separatoris disposed between a first electrode plateand a second electrode plateadjacent to each other, to reduce the risk of short circuits caused by direct contact between the first electrode plateand the second electrode plate.

30 40 20 10 21 211 212 212 211 30 211 22 221 222 222 221 40 221 The first metal plateand the second metal plateare electrically connected to the electrode assemblyand extend out of the housingto be connected to external components (not shown in the figure). Specifically, the first electrode plateincludes a first current collectorand a first active material layer, the first active material layeris disposed on at least one surface of the first current collector, and the first metal plateis electrically connected to the first current collector. The second electrode plateincludes a second current collectorand a second active material layer, the second active material layeris disposed on at least one surface of the second current collector, and the second metal plateis electrically connected to the second current collector.

21 22 211 212 221 222 In some embodiments, the first electrode plateis a positive electrode plate, and the second electrode plateis a negative electrode plate. Specifically, the first current collectorincludes at least one of Ni, Ti, Cu, Ag, Au, Pt, Fe, Al, and compositions thereof. The first active material layerincludes a positive electrode active material. The positive electrode active material may include at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium iron manganese phosphate, lithium vanadium phosphate, lithium vanadium oxide, a lithium-rich manganese-based material, lithium nickel cobalt aluminate, and a composition thereof. The second current collectorincludes at least one of Ni, Ti, Cu, Ag, Au, Pt, Fe, Al, and a composition thereof. The second active material layerincludes a negative electrode active material. The negative electrode active material may be selected from at least one of a graphite-based material, an alloy-based material, lithium metal, and an alloy thereof. The graphite-based material may be selected from at least one of artificial graphite and natural graphite; and the alloy-based material may be selected from at least one of silicon, silicon oxide, tin, and titanium sulfide.

2 FIG. 4 FIG. 20 201 202 203 204 205 206 201 202 201 202 201 202 203 204 201 202 30 40 203 30 40 10 10 205 206 201 202 20 20 30 40 Referring toto, the electrode assemblyfurther includes a first surface, a second surface, a second end face, a first end face, a first side face, and a second side face. The first surfaceand the second surfaceare opposite each other in a first direction Z. In the first direction Z, surfaces of two outermost electrode plates among the plurality of electrode plates serve as the first surfaceand the second surface, respectively. In some embodiments, surfaces of current collectors of the two outermost electrode plates among the plurality of electrode plates serve as the first surfaceand the second surface. The second end faceand the first end faceare opposite each other in a second direction Y and are connected between the first surfaceand the second surface. The first metal plateand the second metal plateextend from the second end face. The first metal plateand the second metal platemay directly extend out of the housing, or may be connected to another metal plate, and this another metal plate extends out of the housing. The first side faceand the second side faceare opposite each other in a third direction X and are connected between the first surfaceand the second surface. In this application, the third direction X refers to a width direction of the electrode assembly, and the second direction Y refers to a length direction of the electrode assembly, where the second direction Y is also a direction in which the first metal plateand the second metal plateextend out, and the first direction Z, the third direction X, and the second direction Y are perpendicular to each other.

23 23 23 23 23 21 22 23 23 20 21 23 22 23 23 21 22 23 23 203 204 23 23 205 206 a a a a a a a a a The first separatorincludes at least one first portiondisposed in the plurality of electrode plates. In some embodiments, the first separatorincludes a plurality of first portions, and each first portionis configured to separate a first electrode plateand a second electrode plateadjacent to each other. The plurality of first portionsare separately arranged, to be specific, the plurality of first portionsare configured as separate separators. In this case, the electrode assemblyis obtained by alternately stacking the first electrode plate, the first portions, and the second electrode plate. An edge of the first portionof the first separatorextends beyond edges of the electrode plates in both the third direction X and the second direction Y to separate the adjacent first electrode plateand second electrode plate. End faces of two sides of the first portionof the first separatorin the second direction Y serve as the second end faceand the first end face, respectively, and end faces of two sides the first portionof the first separatorin the third direction X serve as the first side faceand the second side face, respectively.

2 FIG. 3 FIG. 5 FIG. 5 FIG. 100 50 50 201 202 204 201 202 204 50 201 202 50 20 21 22 23 23 204 204 a Referring to,, and, the electrochemical apparatusfurther includes a first insulating layer. The first insulating layeris substantially sheet-shaped, covering at least a portion of the first surface, at least a portion of the second surface, and at least a portion of the first end face, and is adhered to all the first surface, the second surface, and the first end face. In, the first insulating layeris connected to surfaces, serving as the first surfaceand the second surface, of current collectors of the two electrode plates. The first insulating layerconstrains the electrode assemblyin the first direction Z and the second direction Y, reducing the risk of short circuits caused by contact between the first electrode plateand the second electrode platedue to shrinkage of the first portionof the first separatorclose to the first end facein the second direction Y during thermal abuse or mechanical abuse, and also reducing stress on the first end faceduring a drop, thereby reducing the risk of electrode plate damage.

2 FIG. 3 FIG. 20 50 50 50 204 50 23 23 50 204 1 2 1 2 1 2 1 2 1 Referring toand, a width of the electrode assemblyin the third direction X is defined as W, and a width of the first insulating layerin the third direction X is defined as W, where 0.7W≤W≤W. When W<0.7W, the width of the first insulating layeris small, and a connection area between the first insulating layerand the first end faceis small, that is, a connection area between the first insulating layerand the first separatoris small, which makes the first separatorprone to shrinkage during hot box and drop tests, leading to internal short circuits. In some embodiments, W≤0.95W, which is conducive to balancing the tolerance for arranging the first insulating layerduring manufacturing and improving the electrolyte infiltration effect at the first end face.

2 FIG. 4 FIG. 100 60 70 60 201 202 205 201 202 205 60 20 23 23 205 70 201 202 206 201 202 206 70 20 23 23 206 a a Referring toto, in some embodiments, the electrochemical apparatusfurther includes a fourth insulating layerand a third insulating layer. The fourth insulating layeris substantially sheet-shaped, covering at least a portion of the first surface, at least a portion of the second surface, and at least a portion of the first side face, and is connected to all the first surface, the second surface, and the first side face. The fourth insulating layerconstrains the electrode assemblyin the first direction Z and the third direction X, reducing the risk of shrinkage of an end of the first portionof the first separatorclose to the first side facein the third direction X. The third insulating layeris substantially sheet-shaped, covering at least a portion of the first surface, at least a portion of the second surface, and at least a portion of the second side face, and is connected to all the first surface, the second surface, and the second side face. The third insulating layerconstrains the electrode assemblyin the first direction Z and the third direction X, reducing the risk of shrinkage of an end of the first portionof the first separatorclose to the second side facein the third direction X.

2 FIG. 3 FIG. 5 FIG. 100 80 80 201 202 203 201 202 203 80 20 23 23 203 100 80 80 30 40 80 30 205 80 40 206 80 203 80 203 23 23 203 a a Referring to,, and, in some embodiments, the electrochemical apparatusfurther includes a second insulating layer. The second insulating layeris substantially sheet-shaped, covering at least a portion of the first surface, at least a portion of the second surface, and a portion of the second end face, and is connected to all the first surface, the second surface, and the second end face. The second insulating layerconstrains the electrode assemblyin the first direction Z and the second direction Y, reducing the risk of shrinkage of an end of the first portionof the first separatorclose to the second end facein the second direction Y. In these embodiments, the electrochemical apparatusincludes three second insulating layers, where one second insulating layeris disposed between the first metal plateand the second metal plate, one second insulating layeris disposed between the first metal plateand the first side face, and one second insulating layeris disposed between the second metal plateand the second side face, thereby increasing a connection area between the second insulating layerand the second end face, maintaining the adhesive strength between the second insulating layerand the second end face, and further reducing the risk of shrinkage of the end of the first portionof the first separatorclose to the second end face.

50 60 70 80 20 50 60 70 80 In some embodiments, the first insulating layer, the fourth insulating layer, the third insulating layer, and the second insulating layerare all adhesive and adhered to the electrode assembly. Materials of the first insulating layer, the fourth insulating layer, the third insulating layer, and the second insulating layermay each be a single-sided adhesive or a double-sided adhesive.

6 FIG. 23 231 232 231 232 21 232 22 232 232 50 20 1 1 1 1 Referring to, the first separatorhas a laminated film structure. Specifically, the first separator includes a substrate layerand a plurality of first coatingsspaced apart on one surface of the substrate layer, where the first coatingis adhered to the first electrode plate. In another embodiment, the first coatingmay alternatively be adhered to the second electrode plate. A gap Gexists between two adjacent first coatings. The gaps Gamong the plurality of first coatingsreserve space for electrolyte transport, allowing the electrolyte to flow through the gaps Gand fully infiltrate the electrode plate after electrolyte injection. In this case, even if the first insulating layeris provided to constrain the electrode assemblyin the first direction Z and the second direction Y, the electrolyte can still infiltrate the electrode plate through the gaps G.

232 232 232 232 231 232 232 231 23 232 232 23 100 100 20 100 a b a b a b b In one embodiment, the first coatingincludes a first inorganic particle layerand a first adhesive layerstacked together. The first inorganic particle layeris in connected to the substrate layer, the first adhesive layeris disposed on a surface of the first inorganic particle layerfacing away from the substrate layer, and the first separatoris adhered to an adjacent electrode plate through the first adhesive layer. The first adhesive layermay be adhered to the electrode plate, enhancing the interfacial adhesive strength between the first separatorand the electrode plate and reducing swelling deformation caused by gas generation inside the electrochemical apparatus, that is, enhancing the deformation resistance of the electrochemical apparatusand reducing the risk of deformation and structural damage of the electrode assembly, thereby improving the cycling performance of the electrochemical apparatus.

7 FIG. 232 231 232 231 231 232 231 232 231 232 232 232 23 20 232 23 20 a a a 1 1 1 1 Referring to, the first coatingis strip-shaped and disposed on a surface of the substrate layer, and the plurality of first coatingsare arranged parallel to each other. The substrate layerincludes two side edgesopposite each other in the second direction Y. An included angle between the first coatingand the side edgeis 01. The first coatingis obliquely disposed with respect to the side edge, to be specific, 0°<θ<90°, so that the adhesive strength between the first coatingand the electrode plate is continuously distributed across edges of the electrode assembly in the second direction Y and the third direction X, enhancing the deformation resistance of the electrode assembly and improving cycling performance. In some embodiments, 25°≤θ≤65°, which maintains the adhesive strength between the first coatingand the electrode plate edge and suppresses edge deformation of the electrode plate, thereby improving the cycling performance. When θ<25°, since the first coatingis aligned to the third direction X, the adhesivity between the first separatorand the electrode plate in the second direction Y may decrease, potentially causing deformation of the edge of the electrode assemblyin the third direction X, thereby affecting the cycle life. When θ>65°, since the first coatingis aligned to the second direction Y, the adhesivity between the first separatorand the electrode plate in the third direction X may decrease, potentially causing deformation of the edge of the electrode assemblyin the second direction Y, thereby affecting the cycle life.

7 FIG. 232 232 232 1 2 1 2 2 1 2 1 2 2 1 2 As shown in, in some embodiments, when viewed along the first direction Z, a width of the first coatingis D, and a spacing between two adjacent first coatingsis D, where Dand Dsatisfy: 0.3D≤D≤0.5D. When D>0.5D, upon a fixed electrode plate area, a smaller Dreduces the space available for electrolyte transport, which causes poor electrolyte infiltration, resulting in lithium precipitation issues on the electrode plate, and affecting the cycling performance. When D<0.3D, an adhesion area between the first coatingand the electrode plate is reduced, the adhesive strength is reduced, the deformation resistance is reduced accordingly, affecting cycling performance.

6 FIG. 23 233 231 231 232 233 232 21 233 22 233 233 2 As shown in, in some embodiments, the first separatorfurther includes a plurality of second coatingsspaced apart on one surface of the substrate layer, with the substrate layerlocated between the first coatingand the second coating. When the first coatingis adhered to the first electrode plate, the second coatingis adhered to the second electrode plate. A gap Gexists between two adjacent second coatings, serving as a channel for electrolyte transport. Thus, the provision of the second coatingfurther improves the electrolyte infiltration effect, further reducing lithium precipitation issues on the electrode plate caused by poor electrolyte infiltration, thereby improving the cycling performance.

233 233 233 233 231 233 233 231 a b a b a The second coatingincludes a second inorganic particle layerand a second adhesive layerstacked together. The second inorganic particle layeris in connected to the substrate layer, and the second adhesive layeris disposed on a surface of the second inorganic particle layerfacing away from the substrate layer.

231 232 233 231 In some embodiments, the substrate layerincludes a polymer film, a multilayer polymer film, or a non-woven fabric formed from any one or a mixture of two or more of the following polymers: polyolefin, polyvinylidene fluoride, polyethylene terephthalate, cellulose, polyimide, polyamide, spandex, and poly-paraphenylene terephthalamide. These polymers have high thermal stability and are easily subjected to surface treatment, facilitating the application of the first coatingand the second coatingon the substrate layer. Additionally, these polymers have good toughness and are easy to bend.

232 233 232 233 a a a a The first inorganic particle layerand the second inorganic particle layereach include an inorganic particle material, where the inorganic particle material includes at least one of boehmite particles, aluminum hydroxide particles, or magnesium hydroxide particles. The first inorganic particle layerand the second inorganic particle layermay further include a binder, where the binder adheres the inorganic particle material together. The binder may include polyvinylidene fluoride or a copolymer of vinylidene fluoride-hexafluoropropylene.

232 233 23 21 22 b b The first adhesive layerand the second adhesive layereach include an adhesive material, where the adhesive material includes at least one of the following polymers: a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of vinylidene fluoride-trichloroethylene, polymethyl methacrylate, polyacrylic acid, polyacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, a copolymer of ethylene-vinyl acetate, polyimide, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, a copolymer of acrylonitrile-styrene-butadiene, polyvinyl alcohol, polyvinyl ether, polytetrafluoroethylene, polyhexafluoropropylene, a copolymer of styrene-butadiene, or polyvinylidene fluoride. These polymers can provide strong adhesion, adhering the first separatorto the first electrode plateor the second electrode plate.

8 FIG. 233 233 233 231 233 231 233 233 23 20 233 23 20 a a 2 2 2 2 2 Referring to, in some embodiments, the second coatingis strip-shaped, and the plurality of second coatingsare arranged parallel to each other. An included angle between the second coatingand the side edgeis θ. The second coatingis obliquely disposed with respect to the side edge, to be specific, 0°<θ<90°. In some embodiments, 25°≤θ≤65°, which maintains the adhesive strength between the second coatingand the electrode plate edge and further suppresses edge deformation of the electrode plate, thereby improving the cycling performance. When θ<25°, since the second coatingis aligned to the third direction X, the adhesivity between the first separatorand the electrode plate in the second direction Y may decrease, potentially causing deformation of the edge of the electrode assemblyin the third direction X, thereby affecting the cycle life. When θ>65°, since the second coatingis aligned to the second direction Y, the adhesivity between the first separatorand the electrode plate in the third direction X may decrease, potentially causing deformation of the edge of the electrode assemblyin the second direction Y, thereby affecting cycle life.

8 FIG. 9 FIG. 232 233 232 233 232 233 232 233 232 231 2 233 231 3 3 1 2 1 a a. As shown in, the first coatingand the second coatingare spatially interdigitated, with an included angle between the first coatingand the second coatingbeing θ, where 0°<θ<180°. Thus, the gaps Gamong the plurality of first coatingsand the gaps Gamong the plurality of second coatingsare staggered, further improving the electrolyte infiltration effect. As shown in, in another embodiment, the first coatingand the second coatingmay alternatively be arranged parallel to each other. In this case, the included angle θbetween the first coatingand the side edgeis equal to the included angle θbetween the second coatingand the side edge

9 FIG. 232 233 231 232 231 231 233 231 231 232 233 1 2 3 a a a a Referring to, the first coatingsor the second coatingsmay be discontinuously disposed, for example, being disposed as a plurality of blocks or a plurality of islands on the surface of the substrate layer. In this case, the included angle θbetween the first coatingand the side edgerefers to an included angle between a line connecting the plurality of block portions or island portions and the side edge, and the included angle θbetween the second coatingand the side edgerefers to an included angle between a line connecting the plurality of block portions or island portions and the side edge. Gaps Gare also provided within the first coatingsdiscontinuously disposed or the second coatingsdiscontinuously disposed, capable of serving as channels for electrolyte transport, thereby further improving electrolyte transport performance.

10 FIG. 23 23 23 23 23 23 23 a Referring to, in another embodiment, the plurality of first portionsof the first separatorare disposed, that is, the first separatoris integrally disposed. The first separatorhas a Z-shaped folded structure. Specifically, in the first direction Z, the first separatoris bent in a Z-shape to form the Z-shaped folded structure. The first separatorwith the Z-shaped folded structure has only two end portions, reducing the risk of internal short circuits caused by shrinkage of the first separator, thereby improving the safety performance.

11 FIG. 11 FIG. 23 23 23 23 201 20 23 202 20 23 23 23 23 23 23 23 24 23 24 23 24 b c b c a b c a a a a Referring to, in another embodiment, the first separatorfurther includes a second portionand a third portionlocated outside the plurality of electrode plates and opposite each other in the first direction Z, where a surface of the second portionfacing away from the electrode plates serves as the first surfaceof the electrode assembly, which is connected to the first insulating layer, and a surface of the third portionfacing away from the electrode plates serves as the second surfaceof the electrode assembly, which is connected to the first insulating layer. The plurality of first portions, the second portion, and the third portionof the first separatorare integrally formed to form a wound structure, with the plurality of electrode plates located within the wound structure. Specifically, the first separatoris wound around one of its ends in the second direction Y to sequentially wind every n electrode plates to form the wound structure, where n is an integer greater than or equal to 1. That is, n electrode plates are disposed between every two adjacent first portions.shows that three electrode plates are disposed between two adjacent first portions. When n is greater than or equal to 2, second separatorsare disposed among the plurality of electrode plates between two adjacent first portions. The second separatoris made of an insulating material to prevent short circuits caused by direct contact between the plurality of electrode plates between two adjacent first portions. The material of the second separatormay include at least one of polyolefin, polyvinylidene fluoride, polyethylene terephthalate, cellulose, polyimide, polyamide, spandex, or poly-paraphenylene terephthalamide.

23 23 20 20 23 23 23 23 50 23 23 23 23 50 20 50 b c b c The integrally formed first separatoris configured as a wound structure, allowing the entire first separatorto constrain the plurality of electrode plates in the first direction Z and the third direction X, without providing additional second insulating layer and third insulating layer to constrain the electrode assemblyin the first direction Z and the third direction X. As compared to a solution of providing a second insulating layer and a third insulating layer to constrain the electrode assemblyin the first direction Z and the third direction X, the first separatorconfigured as a wound structure provides weaker constraint on the edges of the electrode plates in the third direction X, helping the electrolyte to flow through the edges of the electrode plates in the third direction X and fully infiltrate the electrode plates. Furthermore, the first separatorincludes the second portionand the third portionlocated outside the plurality of electrode plates, and the first insulating layeris connected to the second portionand the third portionof the first separator. A surface roughness of the first separatoris greater than a surface roughness of the current collector of the electrode plate, increasing the adhesive strength between the first insulating layerand the electrode assembly, thereby reducing the risk of detachment of the first insulating layer.

12 FIG. 1 1 100 1 Referring to, an embodiment of this application further provides an electric device. The electric deviceincludes the electrochemical apparatusdescribed above. The electric deviceof this application may be, but is not limited to, a laptop computer, a pen-input computer, a mobile computer, an e-book reader, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, a liquid crystal display television, a portable cleaner, a portable CD player, a mini-disc player, a transceiver, an electronic organizer, a calculator, a memory card, a portable recorder, a radio, a backup power source, a motor, an automobile, a motorcycle, an electric bicycle, a bicycle, a lighting device, a toy, a game console, a clock, an electric tool, a flashlight, a camera, a large household storage battery, or a lithium-ion capacitor.

The following provides a detailed description of this application through specific examples and comparative examples. An example in which the electrochemical apparatus is a pouch battery is used to describe this application in conjunction with specific preparation processes and testing methods. Those skilled in the art should understand that the preparation methods described in this application are only examples, and any other suitable preparation methods are within the scope of this application.

1 2 1 2 1 A slurry formed by mixing an inorganic particle material and a binder was intermittently applied onto a surface of a substrate layer to form a plurality of first inorganic particle layers spaced apart, and then an adhesive material was applied onto surfaces of the plurality of first inorganic particle layers to form a plurality of first adhesive layers, to obtain a plurality of first coatings spaced apart. Subsequently, the slurry formed by mixing the inorganic particle material and the binder was intermittently applied onto another surface of the substrate layer to form a plurality of second inorganic particle layers spaced apart, and then the adhesive material was applied onto surfaces of the plurality of second inorganic particle layers to form a plurality of second adhesive layers, to obtain a plurality of second coatings spaced apart, thereby obtaining a first separator. A width Dof the first coating and a distance Dbetween two adjacent first coatings satisfied a relationship D=0.3D, and an included angle θbetween the first coating and a side edge of the substrate layer was 45°.

2 1 2 1 The first separator and a plurality of electrode plates were wound to obtain an electrode assembly, where the first separator had a wound structure, three electrode plates were disposed between two adjacent first portions of the first separator, and surfaces of a second portion and a third portion of the first separator facing away from the electrode plates served as a first surface and a second surface of the electrode assembly. A first insulating layer was adhered to the first surface, the second surface, and a second end face of the electrode assembly, where a width Wof the first insulating layer and a width Wof the electrode assembly satisfied a relationship: W=0.8W.

The electrode assembly and an electrolyte were encapsulated in an aluminum-plastic film to obtain an electrochemical apparatus.

1 2 2 1 1 Examples 2 to 13 differed from Example 1 in that at least one of a value of D/D, a value of W/W, and a value of the included angle θwas different.

Comparative Example 1 differed from Example 1 in that the slurry was continuously applied onto a surface of the substrate layer to form a first inorganic particle layer and a second inorganic particle layer, and the slurry was continuously applied onto a surface of the first inorganic particle layer and a surface of the second inorganic particle layer to form a first adhesive layer. To be specific, the plurality of first coatings and the plurality of second coatings spaced apart in Example 1 were integrally connected, respectively.

Cycling tests were performed on the electrochemical apparatuses of Comparative Example 1 and Examples 1 to 10, 12, and 13, with the test results recorded in Table 1. Steps of the cycling tests included: at 45° C., the electrochemical apparatus was charged to 4.43 V at a constant current of 1C, charged at a constant voltage to 0.05C, left standing for 5 min, and then discharged to 3.0 V at 0.7C. A discharge capacity at this time was measured using a commercially available battery performance tester, which was recorded as an initial discharge capacity of the electrochemical apparatus, denoted as 100%. The above charge-discharge steps were cycled 1000 times, and a ratio of the discharge capacity of the electrochemical apparatus after cycling to the initial capacity of the electrochemical apparatus was multiplied by 100%, to obtain a capacity retention rate. The electrochemical apparatus was fully charged according to a charging process and disassembled, and an interface condition and a lithium precipitation condition of a negative electrode plate were observed.

TABLE 1 Cycling capacity Interface condition of 2 1 W/W 1 2 D/D 1 θ retention rate negative electrode plate Comparative 0.8 / / 55% Poor electrolyte infiltration, Example 1 significant purple spots with lithium precipitation in main region Example 1 0.8 0.3 45° 88% Good interface condition in main region, few purple spots with lithium precipitation in edge region Example 2 0.8 0.4 45° 85% Good interface condition in main region, few purple spots with lithium precipitation in edge region Example 3 0.8 0.5 45° 86% Good interface condition in main region, few purple spots with lithium precipitation in edge region Example 4 0.7 0.4 45° 83% Good interface condition in main region, few purple spots with lithium precipitation in edge region Example 5 0.85 0.4 45° 88% Good interface condition in main region, no purple spots with lithium precipitation in edge region Example 6 1 0.4 45° 88% Good interface condition in main region, no purple spots with lithium precipitation in edge region Example 7 0.8 0.4 25° 83% Good interface condition in main region, few purple spots with lithium precipitation in edge region Example 8 0.8 0.4 65° 82% Good interface condition in main region, few purple spots with lithium precipitation in edge region Example 9 0.8 0.2 45° 67% Poor interface condition caused by severe deformation of electrochemical apparatus, purple spots with lithium precipitation in main region Example 10 0.8 0.6 45° 63% Poor electrolyte infiltration, purple spots with lithium precipitation in main region Example 12 0.8 0.4 20° 69% Poor interface condition caused by long edge deformation, purple spots with lithium precipitation Example 13 0.8 0.4 70° 71% Poor interface condition caused by wide edge deformation, purple spots with lithium precipitation

From the comparison between Comparative Example 1 and Examples 1 to 10, 12, and 13, it can be seen that when a first insulating layer with a larger width is used to constrain the electrode assembly in the first direction, continuous application of the first coating and the second coating on two surfaces of the substrate layer leads to serious poor electrolyte infiltration, resulting in occurrence of significant purple spots with lithium precipitation in the main region of the electrode plate (a region close to the center of the electrode plate), thereby affecting the lifespan of the electrochemical apparatus. In contrast, intermittent application of the first coating and the second coating on two surfaces of the substrate layer reserves gaps between adjacent first coatings and adjacent second coatings for electrolyte transport, improving the electrolyte infiltration effect and extending the lifespan of the electrochemical apparatus. Therefore, Comparative Example 1 has the lowest cycling capacity retention rate.

2 1 1 1 From the comparison between Examples 1 to 3 and Examples 9 and 10, it can be seen that when 0.3D≤D≤0.5 is satisfied, the negative electrode plate has a good interface condition after cycling, and the electrochemical apparatus has a high capacity retention rate. When Dis too small, an adhesion area between the first separator and the electrode plate is too small, reducing the overall mechanical strength of the electrochemical apparatus, and easily causing deformation during cycling which leads to a poor interface condition. When Dis too large, the space reserved for electrolyte transport on the first separator is too small, leading to poor infiltration and consequently resulting in a poor interface condition.

1 1 From the comparison between Examples 2, 7, 8, 12, and 13, it can be seen that when 25°≤θ≤65° is satisfied, the negative electrode plate has a good interface condition after cycling, and the electrochemical apparatus has a high capacity retention rate. When θis too small or too large, the edge of the electrode plate is prone to deformation, leading to a poor interface condition.

1 2 2 1 2 1 From the comparison between Examples 2 and Examples 4 to 6, it can be seen that when 0.7W≤Wis satisfied, the negative electrode plate has a good interface condition after cycling, and the electrochemical apparatus has a high capacity retention rate. As W/Wincreases, the cycling capacity retention rate shows a trend of increasing first and then remaining constant, and when W≥0.85W, the electrochemical apparatus has a higher capacity retention rate.

Hot box tests were performed on the electrochemical apparatuses of Comparative Example 1, Example 2, and Example 14, with the test results recorded in Table 2. Steps of the hot box tests included: at 25±5° C., the electrochemical apparatus was charged to 4.43 V at a constant current of 0.2C, and then charged at a constant voltage to 0.01C. The electrochemical apparatus was heated at a rate of 5±2° C./min to 140±2° C. and maintained for 60 min. Whether the electrochemical apparatus exhibited failure phenomena such as fire or explosion was observed. If no failure phenomena occurred, the electrochemical apparatus was considered to pass the hot box test; otherwise, the electrochemical apparatus failed to pass the test. The pass rates of 20 electrochemical apparatuses in the hot box test were statistically recorded. After the test, each electrochemical apparatus was disassembled to observe whether there was separator shrinkage.

TABLE 2 Hot box test Phenomena after 2 1 W/W 1 2 D/D 1 θ pass rate disassembly Comparative 0.8 / /  0% Electrochemical apparatus Example 1 caught fire, severe shrinkage of first separator was observed Example 2 0.8 0.4 45° 100% Electrochemical apparatus did not catch fire, no significant shrinkage of first separator was observed

From the comparison between Comparative Example 1 and Example 2, it can be seen that when surfaces of the second portion and the third portion of the first separator serve as the first surface and the second surface of the electrode assembly, that is, when the electrode assembly is terminated with the first separator, intermittently applying the first coating and the second coating onto two surfaces of the substrate layer improves the hot box test pass rate and mitigates shrinkage of the first separator.

Drop tests were performed on the electrochemical apparatuses of Examples 1 to 6, 9, and 11, with the test results recorded in Table 3. Steps of the drop tests included: at 25±5° C., the electrochemical apparatus was charged to 4.43 V at a constant current of 0.2C, and then charged at a constant voltage to 0.01C. The electrochemical apparatus was fixed to a drop test fixture and dropped 6 times sequentially from 6 surfaces of the drop test fixture at a height of 1.8 m. After each drop, whether the electrochemical apparatus was damaged was observed and an open-circuit voltage of the electrochemical apparatus was recorded. If the voltage was less than 3.0 V, the electrochemical apparatus was deemed failed. If no damage occurred and the open-circuit voltage was higher than 3.0 V, the electrochemical apparatus was deemed not failed, and the test was continued until the failed, and the number of drops after which the electrochemical apparatus failed was recorded. Subsequently, the electrochemical apparatus was disassembled for analysis, and whether there was separator shrinkage was observed.

TABLE 3 Number of failures 2 1 W/W 1 2 D/D 1 θ after drop Example 1 0.8 0.3 45° 42 Example 2 0.8 0.4 45° 43 Example 3 0.8 0.5 45° 45 Example 4 0.7 0.4 45° 41 Example 5 0.85 0.4 45° 44 Example 6 1 0.4 45° 44 Example 9 0.8 0.2 45° 32 Example 11 0.5 0.4 45° 25

2 1 2 1 From the comparison between Examples 1-3 and Example 9, it can be seen that when 0.3D≤D≤0.5Dis satisfied, the electrochemical apparatus withstands more drops, indicating better drop resistance. When Dis too small, the adhesion area between the first separator and the electrode plate is small, limiting the overall constraining effect of the first separator on the electrode assembly, and increasing mutual impact between the electrode plates and between the electrode assembly and the housing, thereby easily leading to housing damage. Therefore, the electrochemical apparatus in Example 9 has the worst drop resistance.

1 2 2 From the comparison between Examples 2, 4-6, and 11, it can be seen that when 0.7W≤Wis satisfied, the electrochemical apparatus withstands more drops, indicating better drop resistance. In Example 11, Wis too small, leading to failure caused by shrinkage of the first separator during drops, with the fewest drops and the worst drop resistance.

The above disclosures are only preferred embodiments of this application and certainly cannot limit this application. Therefore, equivalent changes made in accordance with this application still fall within the scope of this application.